Auto merge of #21543 - alexcrichton:old-io, r=aturon

In preparation for the I/O rejuvination of the standard library, this commit
renames the current `io` module to `old_io` in order to make room for the new
I/O modules. It is expected that the I/O RFCs will land incrementally over time
instead of all at once, and this provides a fresh clean path for new modules to
enter into as well as guaranteeing that all old infrastructure will remain in
place for some time.

As each `old_io` module is replaced it will be deprecated in-place for new
structures in `std::{io, fs, net}` (as appropriate).

This commit does *not* leave a reexport of `old_io as io` as the deprecation
lint does not currently warn on this form of use. This is quite a large breaking
change for all imports in existing code, but all functionality is retained
precisely as-is and path statements simply need to be renamed from `io` to
`old_io`.

[breaking-change]

1 files changed, 5 insertions, 5 deletions

diff --git a/src/test/debuginfo/function-arg-initialization.rs b/src/test/debuginfo/function-arg-initialization.rs
index 55c5c504064..38875c7656e 100644
--- a/src/test/debuginfo/function-arg-initialization.rs
+++ b/src/test/debuginfo/function-arg-initialization.rs
@@ -226,7 +226,7 @@
 #![omit_gdb_pretty_printer_section]
 
 fn immediate_args(a: int, b: bool, c: f64) {
-    ::std::io::print("") // #break
+    ::std::old_io::print("") // #break
 }
 
 struct BigStruct {
@@ -241,21 +241,21 @@ struct BigStruct {
 }
 
 fn non_immediate_args(a: BigStruct, b: BigStruct) {
-    ::std::io::print("") // #break
+    ::std::old_io::print("") // #break
 }
 
 fn binding(a: i64, b: u64, c: f64) {
     let x = 0i; // #break
-    ::std::io::print("")
+    ::std::old_io::print("")
 }
 
 fn assignment(mut a: u64, b: u64, c: f64) {
     a = b; // #break
-    ::std::io::print("")
+    ::std::old_io::print("")
 }
 
 fn function_call(x: u64, y: u64, z: f64) {
-    std::io::stdio::print("Hi!") // #break
+    std::old_io::stdio::print("Hi!") // #break
 }
 
 fn identifier(x: u64, y: u64, z: f64) -> u64 {